2 * Xtensa KASAN shadow map initialization
4 * This file is subject to the terms and conditions of the GNU General Public
5 * License. See the file "COPYING" in the main directory of this archive
8 * Copyright (C) 2017 Cadence Design Systems Inc.
11 #include <linux/memblock.h>
12 #include <linux/init_task.h>
13 #include <linux/kasan.h>
14 #include <linux/kernel.h>
15 #include <asm/initialize_mmu.h>
16 #include <asm/tlbflush.h>
17 #include <asm/traps.h>
19 void __init kasan_early_init(void)
21 unsigned long vaddr = KASAN_SHADOW_START;
22 pgd_t *pgd = pgd_offset_k(vaddr);
23 pmd_t *pmd = pmd_offset(pgd, vaddr);
26 for (i = 0; i < PTRS_PER_PTE; ++i)
27 set_pte(kasan_zero_pte + i,
28 mk_pte(virt_to_page(kasan_zero_page), PAGE_KERNEL));
30 for (vaddr = 0; vaddr < KASAN_SHADOW_SIZE; vaddr += PMD_SIZE, ++pmd) {
31 BUG_ON(!pmd_none(*pmd));
32 set_pmd(pmd, __pmd((unsigned long)kasan_zero_pte));
37 static void __init populate(void *start, void *end)
39 unsigned long n_pages = (end - start) / PAGE_SIZE;
40 unsigned long n_pmds = n_pages / PTRS_PER_PTE;
42 unsigned long vaddr = (unsigned long)start;
43 pgd_t *pgd = pgd_offset_k(vaddr);
44 pmd_t *pmd = pmd_offset(pgd, vaddr);
45 pte_t *pte = memblock_alloc(n_pages * sizeof(pte_t), PAGE_SIZE);
47 pr_debug("%s: %p - %p\n", __func__, start, end);
49 for (i = j = 0; i < n_pmds; ++i) {
52 for (k = 0; k < PTRS_PER_PTE; ++k, ++j) {
54 memblock_alloc_base(PAGE_SIZE, PAGE_SIZE,
55 MEMBLOCK_ALLOC_ANYWHERE);
57 set_pte(pte + j, pfn_pte(PHYS_PFN(phys), PAGE_KERNEL));
61 for (i = 0; i < n_pmds ; ++i, pte += PTRS_PER_PTE)
62 set_pmd(pmd + i, __pmd((unsigned long)pte));
64 local_flush_tlb_all();
65 memset(start, 0, end - start);
68 void __init kasan_init(void)
72 BUILD_BUG_ON(KASAN_SHADOW_OFFSET != KASAN_SHADOW_START -
73 (KASAN_START_VADDR >> KASAN_SHADOW_SCALE_SHIFT));
74 BUILD_BUG_ON(VMALLOC_START < KASAN_START_VADDR);
77 * Replace shadow map pages that cover addresses from VMALLOC area
78 * start to the end of KSEG with clean writable pages.
80 populate(kasan_mem_to_shadow((void *)VMALLOC_START),
81 kasan_mem_to_shadow((void *)XCHAL_KSEG_BYPASS_VADDR));
83 /* Write protect kasan_zero_page and zero-initialize it again. */
84 for (i = 0; i < PTRS_PER_PTE; ++i)
85 set_pte(kasan_zero_pte + i,
86 mk_pte(virt_to_page(kasan_zero_page), PAGE_KERNEL_RO));
88 local_flush_tlb_all();
89 memset(kasan_zero_page, 0, PAGE_SIZE);
91 /* At this point kasan is fully initialized. Enable error messages. */
92 current->kasan_depth = 0;
93 pr_info("KernelAddressSanitizer initialized\n");